1. Field of the Invention
The present invention relates to a rotating electric machine, such as an AC servomotor, and a manufacturing method thereof.
2. Description of the Related Art
In a rotating electric machine, the temperature of a stator coil rises owing to heat loss caused by the driving of the rotating electric machine, and thereby the temperature of the rotating electric machine rises. In particular, in an AC servomotor and the like, a rotation detector, such as an encoder, provided on the opposite load side of the AC servomotor is weak against heat, and consequently it is required to suppress the temperature rising of the rotating electric machine as much as possible.
Accordingly, as a first conventional rotating electric machine, a technique for suppressing the temperature rise of a rotating electric machine by dissipating the heat generated in the stator coil thereof through the frame thereof has been proposed (see, for example, Japanese Patent Application Laid-Open Publication No. 2002-191155).
In the first conventional rotating electric machine, a ceramic, which is a ring-like heat conductor, is inserted between a coil end of a stator coil, wound around a stator core, and a frame. The heat conductor is firmly fixed between the coil end and the frame with a thermosetting resin.
By such a configuration, the heat generated in the stator coil can be transferred from the coil end to the frame through the heat conductor. Thereby, the cooling effect of the rotating electric machine is improved, and the temperature rise thereof can be suppressed. Moreover, more electrification can be performed to the allowable temperature of the stator coil, and consequently the rated output of the rotating electric machine can be improved.
Moreover, as a second conventional rotating electric machine, a technique for suppressing the temperature rise of a rotating electric machine by dissipating the heat generated in the stator coil thereof through the load side bracket thereof effectively has been proposed (see Japanese Patent Application Laid-Open Publication No. 2006-50853).
In the second conventional rotating electric machine, a stator coil composed of a plate-like conductor, which has been produced by stamping out a copper plate having an insulating coat thereon with a press, is mounted on the stator core of the rotating electric machine. The inner circumferential surface and outer circumferential surface of the load side coil end of the stator coil are each formed on a cylindrical surface, and their end surfaces are each formed on a flat surface. Then, the load side coil end is configured to adhere closely to a groove on the load side bracket.
By such a configuration, the heat generated in the stator coil can be transferred from the load side coil end to the load side bracket. Thereby, the cooling effect of the rotating electric machine is improved, and the temperature rise thereof can be suppressed. Moreover, more electrification can be performed to the allowable temperature of the stator coil, and consequently the rated output of the rotating electric machine can be improved.